牛科家畜Plin2基因研究进展*

脂滴广泛存在于多种细胞,作为细胞内中性脂质的主要贮存场所。在脂滴表面的磷脂单分子层上镶嵌着多种蛋白,脂滴包被蛋白家族(Perilipins,PLINs)是脂滴表面含量最多蛋白家族。脂滴包被蛋白通过与脂滴表面特异性位点结合,调节脂类存储与水解。脂滴包被蛋白2(Perilipins2,Plin2)作为脂滴包被蛋白家族重要成员之一,对促进细胞内脂滴形成起着重要作用,在脂质储存、脂质代谢的调节、脂肪酸的氧化及炎症反应等多种生理功能中发挥重要作用。本文综述了Plin2基因的结构、表达和参与的生物学路径,以及其在脂质代谢和脂滴形成中的功能,进一步总结了该基因多态性与生产性状的关联性,可为牛科物种Plin2的深入研究提供参考。     

脂滴功能及其与卵母细胞成熟和胚胎发育的关系研究进展

脂滴不仅是真核细胞内贮存甘油三酯和胆固醇酯等中性脂质的重要细胞器,也是细胞代谢和细胞器质量控制的中心调控者,参与细胞能量代谢、类固醇激素合成、内质网应激、线粒体功能以及生物膜结构形成等过程的调控。目前认为脂滴合成于内质网,并以出芽的方式进入细胞质。脂滴是呈动态分布的细胞器,其数量、大小以及分布受细胞获得营养物质和代谢状态影响。众所周知,哺乳动物卵母细胞含有脂滴,且卵母细胞中含有足够数量的脂滴与卵母细胞成熟和早期胚胎发育密切相关。更重要的是,最近的研究表明,脂滴在胚胎附植着床过程中发挥了至关重要的作用,即使卵母细胞中脂滴含量较低的哺乳动物,维持适量的脂滴对早期胚胎发育也很重要。因此,本文综述了脂滴的合成与分布,分析了脂滴的主要功能,重点阐述脂滴在动物卵母细胞成熟和早期胚胎发育期间的关键作用,并讨论脂滴卵母细胞和胚胎内脂滴含量与胚胎滞育持续时间的关系,以期为通过调控脂滴代谢而增强卵母细胞质量和胚胎发育能力,进而提高动物繁殖性能提供理论基础。     

动物脂滴结构及功能研究进展

脂滴是脂肪组织的基本单位,是维持脂质和能量稳态的一种动态细胞器,脂滴相关蛋白参与调控胞内脂类代谢、膜运输以及信号传导等多个生理过程.脂滴在动物各个组织器官中的功能不尽相同,可通过营养及生理手段调节畜禽外周组织中的脂滴变化,进一步影响畜禽胴体性状及肉品质.本文简述了脂滴的生物学结构、脂滴蛋白分类、脂滴重塑、脂滴生物学功能...     

PLINs基因对脂质的调控及其潜在的育种价值研究进展

周脂素蛋白家族（Perilipins,PLINs）有PLIN1、PLIN2、PLIN3、PLIN4和PLIN5 5种蛋白，该蛋白家族定位于脂滴（Lipid Droplets,LDs）表面，与其他分子相互作用介导脂质的合成与分解。PLIN1可调控脂肪的蓄积，也是脂肪细胞分化的标志物之一。PLIN2是脂质蓄积最重要的调节因子之一，可促进脂质合成，抑制LDs中主要脂质甘油三酯（Triglycerides,TG）和胆固醇酯（Cholesterol Ester,CE）的分解。PLIN3是中性脂质形成的关键基因。PLIN4参与脂肪细胞分化，还可修补脂滴形态的缺陷。PLIN5在LD积累与缓解脂毒性中起关键作用。本文综述了近年关于PLINs家族调控脂质的研究现状及其在畜禽上的应用，旨在阐述其在畜禽生物育种中的潜在育种价值。     

牛乳脂肪球粒径研究进展

乳中脂肪主要以乳脂肪球（milk fat globule，MFG）形式从哺乳动物的乳腺中分泌到乳中，MFG粒径从?0.2 μm到15.0 μm不等，不同粒径MFG影响新生儿的健康及乳制品的理化特性。MFG粒径主要由乳腺上皮细胞中的?脂滴调控，脂滴大小的调控因素包括细胞内甘油三酯水平及其合成与水解过程中参与的酶、膜磷脂、脂滴融合等。本文主要综述MFG的合成和结构、MFG粒径对牛乳营养及乳制品加工的影响、脂滴融合对MFG粒径的调控，为?MFG粒径的应用提供参考。     

饥饿诱发成脂分化C2C12细胞中脂滴形态重塑

试验旨在探究短期饥饿处理对成脂分化C2C12细胞中脂滴生长发育的影响,为阐释及利用补偿生长机制奠定基础。通过胰岛素等激素混合物诱导C2C12细胞成脂分化,将成脂分化12 d的C2C12细胞分为两组：对照组（Control）,高糖培养24 h;饥饿处理组（FAST）,无血清低糖培养24 h。通过BODIPY染色和甘油三酯测定观察脂滴形态变化,并使用Western blotting方法测定脂滴表面结构蛋白perilipin1-5表达量的变化。结果显示,C2C12细胞成脂诱导12 d,可以使细胞达到较好的充脂状态。通过无血清低糖饥饿处理后,成脂分化C2C12细胞中甘油三酯含量极显著下降（P<0.01）;脂滴平均尺寸极显著减小（P<0.01）,脂滴平均数量极显著增多（P<0.01）;脂滴表面结构蛋白出现变化,perilipin2、perilipin5表达极显著上调（P<0.01）、perilipin3表达显著上调（P<0.05）。综上,无血清低糖处理可以诱发脂滴形态重塑,改变脂滴表面结构蛋白的表达。     

围脂滴蛋白(Perilipin)在脂质代谢中的功能

<正>体内能量代谢的核心反应是脂肪细胞的脂解,即脂肪酶将存在于脂滴内的甘油三酯水解为甘油和游离脂肪酸的过程。脂滴是一种亚细胞结构,核心为甘油三酯或胆固醇酯等中性脂质,外周包被着单层磷脂分子,磷脂中镶嵌的脂滴相关蛋白对于脂滴的代谢     

脂滴包被蛋白(perilipin)研究进展

脂滴是脂肪细胞的主要成分,它占据了脂肪细胞的大部分空间,是中性脂质的主要贮存场所.脂滴包被蛋白(perilipin)作为一种重要的脂肪代谢相关蛋白包被于脂滴的表面,perilipin在脂肪代谢调控中起到"分子开关"的作用,对脂滴的代谢具有重要的调控作用.然而perilipin的表达和活性又受到很多因素的调控,如肿瘤坏死...     

脂滴包被蛋白基因对猪肌肉发育的影响

PLIN(perilipin,脂滴包被蛋白)是脂滴表面含量最多的一种蛋白,被认为是影响猪生长、胴体及肉质性状的重要候选基因。PLIN基因几乎在所有组织中均有广泛表达,对脂肪组织中甘油三酯的分解和储存具有重要的双重调控作用,主要调控类固醇激素合成前体、胆固醇酯的分解;通过调节脂肪酶的功能和脂肪沉积来影响肌肉的生长发育并能影响高氧化能力组织内的线粒体功能。本文综述了猪PLIN基因背景、基因结构及组织分布情况,并对近年来PLIN基因对猪肌肉发育影响的研究进行了总结,解析其在骨骼肌发育差异调控网络中的地位和作用,为家猪生产性状改良提供理论依据。     

维生素D受体在体外培养SD大鼠脂肪细胞中的表达

为了探索维生素D受体(VDR)在SD大鼠脂肪细胞分化过程中的表达规律,采用Ⅱ型胶原酶消化法进行SD大鼠脂肪细胞的分离培养,并将其诱导分化为成熟的脂肪细胞,分别在细胞生长至单层汇合后的第0、4、8、12、16天收集细胞样品。对VDR和脂滴进行荧光染色,同时采用Western blot对脂肪细胞分化过程中的VDR蛋白表达量进行分析,采用real-time PCR定量分析脂肪细胞分化过程中的VDR表达量。结果显示,随SD大鼠脂肪细胞的分化,细胞中脂滴逐渐增加,VDR mRNA和蛋白的表达量与脂质积累过程呈负相关性,表明VDR的表达在脂肪细胞分化过程中有一定的变化规律,其可能以负反馈的调节机制参与了脂肪细胞的分化过程。     

Research Progress on Metabolic Related Structural Proteins in Lipid Droplet Development

Generally, lipid droplets are storage of triglycerides in adipocytes, but recent researches indicate that the transport, storage and steatolysis mobilization of fat in the cells are all based on lipid droplets, various phenomena reveal that lipid droplets is not only a simple energy storage in cells, but also more of a multifunctional organelle. By analyzing the structure of lipid droplets, it has been found that with neutral fat as the core, lipid droplets are covered with single phospholipid and embedded with a variety of functional proteins, which are referred as lipid droplets associated proteins. Lipid droplets associated protein correlated with lipid droplets are involved in the regulation of lipid metabolism, membrane transport, signal transduction and other physiological processes in different forms. It can be divided into three categories according to the different bearing capacity of proteins, including lipid droplet structural protein, lipid droplet associated protein and lipid transport protein. Among them, structural proteins, such as proteins in the PAT family and CIDE family proteins, play important roles in the regulation of lipid droplet growth and metabolism.In addition, hormone-sensitive lipase, adipose triglyceride lipase and Rab protein, as well as other metabolism and transport proteins are suggested to be involved in lipid droplets development through different forms. At present, new types and mechanisms of lipid droplets related proteins are still being explored. This review is to address the research progress of lipid droplets, lipid metabolism and lipid droplets related proteins in cells.     

The role of the kidneys in vitamin metabolism

It is well established that the kidney plays an essential role in regulating the homeostasis of body fluids. Recent studies provided evidence for the kidney to be an important organ for the regulation in the metabolism of both fat (vitamin A, D) and water soluble vitamins (e.g. vitamin B12). This regulation is mediated by glomerular filtration as well as reabsorption and secretion processes of protein-bound vitamins. Vitamin transport proteins such as retinol-binding protein, vitamin D-binding protein and transcobalamin II are filtered in renal glomeruli and subsequently reabsorbed in the proximal tubules by endocytosis from the tubular fluid. Megalin, a scavenger receptor belonging to the LDL receptor family, is probably the most important receptor in this process in the proximal tubule cells. The carrier proteins are degraded in lysosomes whereas the vitamins are probably stored, may become coupled to newly synthesized carriers and secreted at the basolateral plasma membrane. A renal vitamin excretion is observed in dogs and other species of the family Canidae, in form of fat soluble retinol and retinyl esters bound to Tamm-Horsfall protein. This and the high vitamin A concentrations in renal tissue of canines suggest an important role of the kidneys in vitamin A metabolism of these species.     

动物脂肪酸转运蛋白1的研究进展

脂肪含量对人类和动物健康以及动物肉品质均有重要影响.脂肪酸转运蛋白1(fatty acid transport protein 1,FATP1)是整合的跨膜蛋白,属于脂肪酸转运蛋白家族(FATPs)成员,参与脂肪酸跨膜转运及脂肪酸代谢,是影响脂肪含量的关键基因之一,近年来引起了越来越多的关注.本文就FATP1的结构特点...     

Adiponectin‐impaired adipocyte differentiation negatively regulates fat deposition in chicken

Adiponectin is a protein hormone secreted exclusively by adipocytes that plays an important role in the modulation of glucose and lipid metabolism. To investigate the effect of adiponectin on lipid metabolism in chicken, rosiglitazone (agonist of adiponectin) and dexamethasone (inhibitor of adiponectin) were used to treat 23‐day‐old broilers in vivo. To verify the functionality of adiponectin on fat deposition, chicken pre‐adipocytes were cultured in the medium containing 10 μg/ml adiponectin. Serum adiponectin and lipids and fat distribution were analysed. Oil Red O staining was used to determine lipid deposition in adipocytes. The expression levels of adiponectin, adiponectin receptors (AdipoR) and lipid metabolism–related genes in different tissues and pre‐adipocytes were measured using real‐time PCR, and the abundance of lipid metabolism–related proteins was measured by Western blot. Rosiglitazone increased serum adiponectin concentration and the expression levels of adiponectin and adiponectin receptor 1 (AdipoR1) in tissues and significantly decreased levels of serum lipids and fat deposition. Rosiglitazone significantly increased the expression levels of adipose triglyceride lipase (ATGL) and AdipoR1 and decreased the expression levels of fatty acid synthase (FAS). Dexamethasone had the converse effects compared with rosiglitazone. Oil red O staining results showed a marked decrease in fat deposition in cells treated with adiponectin. In adipocytes, adiponectin could decrease the expression levels of CCAAT/enhancer‐binding protein α (C/EBPα) and FAS and increased the expression levels of ATGL and AdipoR1. These results indicate that adiponectin has a remarkable effect on impairment of adipocyte differentiation, which contributes to the negative regulation of fat deposition in chicken.     

Starvation Caused Lipid Droplet Remodeling in Adipogenic Differentiation C2C12 Cells

This study was aimed to explore the effect of short-term starvation treatment on the growth and development of lipid droplets in adipogenic differentiation C2C12 cells,provide the foundation for the interpretation and utilization of compensatory growth mechanisms.Adipogenic differentiation C2C12 cells were divided into two groups:Control group,high glucose treatment for 24 h,and starvation treatment group (FAST),serum-free and low-glucose medium starvation treatment for 24 h.The morphological changes of lipid droplets was observed by BODIPY staining and triglyceride determination,and Western blotting was used to determine the change of the expression level of perilipin family protein (perilipin 1-5) on the lipid droplet.The results showed that C2C12 cells induced adipogenesis for 12 days,which could make the cells reach a better fat-filling state.After treatment with serum-free and low-glucose starvation,the levels of triglycerides in adipogenic differentiation C2C12 cells decreased extremely significantly (P<0.01),the size of lipid droplets decreased extremely significantly (P<0.01),and the number of lipid droplets increased extremely significantly (P<0.01).The perilipin protein on the lipid droplets was changed,the expression level of perilipin2 and perilipin5 were extremely significantly up-regulated (P<0.01),and the expression level of perilipin3 was significantly up-regulated (P<0.05).In summary,serum-free and low-glucose starvation could induce the remodeling of lipid droplets and change the expression level of perilipin proteins on the lipid droplets.     

固醇调节元件结合蛋白基因的过表达对促进牛胎儿成纤维细胞脂肪形成的影响

为了研究固醇调节元件结合蛋白(sterol regulatory element binding factor 1,SREBP1)基因的表达与细胞脂肪形成的关系,本研究构建了pEGFP-C1-SREBP1重组质粒,利用脂质体介导法将重组质粒pEGFP-C1-SREBP1及pEGFP-C1空质粒转染至牛胎儿骨骼肌成纤维细胞培养48 h,实时荧光定量PCR和Western blotting分析目标基因表达水平的变化,并采用油红O染色检测细胞内脂滴。结果发现,pEGFP-C1-SREBP1重组质粒转染细胞内SREBP1 mRNA的表达水平显著高于空白对照组和阴性对照组(P<0.05);SREBP1蛋白也出现明显上调;空白对照组和pEGFP-C1阴性对照组细胞内均未见有红染细胞,而pEGFP-C1-SREBP1重组质粒转染组中出现了清晰的红染细胞。说明SREBP1的表达可促进牛胎儿骨骼肌成纤维细胞脂肪合成,证实牛胎儿成纤维细胞中SREBP1表达和脂滴形成之间存在直接关系。     

动物DGAT基因的研究进展

DGAT基因包括二酰基甘油酰基转移酶1（DGAT1）基因和二酰基甘油酰基转移酶2（DGAT2）基因，前者属于酰基辅酶A胆固醇酰基转移酶（ACAT）基因家族，后者属于单酰甘油酰基转移酶（MGAT）基因家族，分别编码微粒体酶DGAT1和DGAT2，这两种酶控制着甘油三酯的合成，均是定位于内质网的跨膜蛋白，其膜拓扑结构具有与其他蛋白质和细胞器相互作用的能力，影响脂肪代谢及脂类在组织中的沉积，参与调节动物机体的能量合成和分解代谢，影响心脏和肝脏中甘油三酯的代谢；同时DGAT基因的多态性影响着牛乳中脂肪的含量及泌乳量。因此，了解DGAT基因的结构和生物学功能对畜禽生长发育和生产等相关研究具有重要的意义。文章简述了DGAT基因的基本结构和生物学功能及相关的作用机制，分析了其在畜牧生产中的基础应用，如参与哺乳动物生产调控的脂肪沉积、乳脂含量等方面的研究进展。